One should note that if you pull the site up in IE it still uses flash, which means we still need flash. Unless you're willing to say goodbye to 40% of your customers.
I'm guessing that you mean 40% of visitors to sites (not the one for the Nissan Leaf) use IE. (Or more specifically IE 6.)
I think it's probably a pretty safe bet that folks who are visiting the Nissan Leaf site, and ESPECIALLY folks who would be early adopters and buy an all-electric car, are probably also not rolling around using IE6. (At least, I'd hope not.)
Conversely, someone being on an iPad or Android device is probably a pretty decent leading indicator that they're in the demographic that would consider buying a Nissan Leaf.
Seriously though, if you were building this site, I'd suggest you'd probably worry a lot more about how it looks on an iPad than a WinXP box running IE6.
The site I work on doesn't even cater to early-adopters the way the Nissan site should, and we have lots more iPad / iPhone / Android traffic than IE6 these days. (And I mean each individually, not in aggregate.)
So it looks like it will use Flash if you have it.